Answer:
Hi there, Here is what I think
Trees can't reduce the negative effects of climate change because climate change throws off their functions (ex. Trees' leaves fall during the fall season but if its a lot warmer close to summer weather during fall season) it can mess up the way they function at a certain point in the seasons with that trees won't be able to function properly if the weather changes all of a sudden from scorching hot summer to a blizzard all of a sudden which can kill trees. Trees can hibernate in the Winter and bloom around Spring/Summer time but if you have wintery weather during summer it will kill them. So no trees can't reduce the negative effects of climate changes hence why people are scared over climate change because if the trees die we can die too without the oxygen trees and other plants provide for us.
Hope this helped :)